"So it's kind of been the theme we've been running here the last few practices, getting guys engaged on the defensive side of the puck," Cooper said. "When that happens, when you're compete-level is going on in practice, it should translate into games."

The Lightning let a two-goal lead slip away Tuesday against a hungry Panthers team chasing down a wild card spot. Cooper said the defensive breakdowns didn't begin in the third period.

"We just weren't defending the way we need to be defending all the way through," Cooper said. It just caught up to us in the third."